Ignition mechanism for oil burners



June 23, 1931. J. N. MACRAE v 1,811,274

IGNITION MEcHANIsM Fox oIL BuRNsRs Filed April, io, 1929 2 sheets-sheet 1 INVENToR.

ATTORNEYS.-

June 23, 1931. J. N. lvlAcFml-z IGNITION MECHANISM FOR OIL VBURNERS Filed April l0, 1929 2 Sheets-Sheet 2 ATTORNEY IN V EN TOR.

Patented June` 23, 1931 JAMES N. MacRAE, E STANFORD, POWER COMPANY, or NEW YORK, .N. Y., A CORPORATION OF DELAWARE IGNITION MEGHANISM FOR OIL BUENERS Application led April 10, 1929. Serial No. 353,950.

CONN ECTIGUT, ASSIGNOR TO PETROLEUM HEAT This invention relates to ignition apparatus particularly designed for use in con- `nection with oil burning installations, and has for one of its objects the provision of an ignition apparatus which is moved into and out of operative position with respect to the fuel to be ignited. In the case of an oil burner installation the apparatus is moved into and out of operative position relatively to the burner nozzle. In this way any damage to the apparatus, due to the heat of the burning fuel, is avoided.

A still further object of the invention is the provision of an ignition apparatus of the general character above referred to in which current is taken direct from a power line, thus avoiding the necessity of` a Step up transformer such as is necessary in spark l gap ignition. Theelimination of the transformer reduces cost, servicing and radio interference. A

A still further object of thev invention is the provision of an ignition apparatus hav ing the characteristics briefly referred to above which is adapted for use with oils having a Hash` point as high as 220 F.,

whereas ignition apparatus now used is adapted for `oils having a flash point between 150 F. to 155, maximum.

This, of course, is of material advantage commercially, while the elimination of the necessity of a transformer such as is required with spark gap apparatus and the ability to plug into the power circuit found on the job lmparts to my improved construction advantages which are material as compared with existing ignition apparatus for oil burning work.

More specifically the present invention provides ignition apparatus adapted to be reciprocated into and out of firing position, the movement of the apparatus out of firing position being accomplished automatically in that the apparatus is returned to initial position by a spring placed under tension by the movementto operative position of the apparatus. Furthermore, the present invention provides a contact control* mechanism whereb the circuit through the `heating element o the igniter is closed when the igniter point of which may be materially higher than those for which spark gap ignition is adapted.

In the drawings accompanying this application Fig. 1 shows more or less diagrammatically installation of my apparatus in connection with an oil burner;

Fig. 2 is a side elevational part sectional View of an embodiment of Fig. 3 is a sectional and Fig. 4 is a section on the line 4 4 of Fig. 2.

my invention; plan view of Fig. 2;

Referring to the 'drawings in detail, my-

apparatus embodies a suitable casing designated 1, so designed as to be bolted or otherwise rigidly secured in the front of a furnace as shown in Fig. l. In order that the igniter element of the apparatus may be brought into proper position relatively to the burner nozzle 2 as will be presently described, the casting l is so designed that the apparatus is set at an angle t`o the burner as is customary'in electrical ignition oil burner apparatus.

The housing or casing-1 is provided with a plurality of rods which may be termed guide rods shown at 3 and 4, screwed or otherwise rigidly secured to the housing as shown for example in Fig. 3. I

5 designatesl a tube which may be. conveniently flanged as shown at 6 and bored for the reception of the guide rods 3 and 4. This tube is adapted to be reciprocated as will appear hereinafter.

Secured'to the front end of the tubular member 5 is an insulating member of a good grade of porcelain designated 7. I have found the material known commercially as to the rear end or rear wall of tubular member 5 is a rod 9, which in the present instance constitutes the operating member by which the igniter element is moved into and out of operative position. This rod 9 is operated t'o the left as viewed in Fig. 3 by a torque motor 10 and a suitable gear train, and is re-V turned to inoperative position by a spring 11. I wish it to be distinctly understood, however, that other mechanism may be employed for effecting reciprocation v of the igniter mechanism, the torque motor and gear train having been shown merely for purposes of illustration. f j

Secured to the rear end of the tubular casing member 5 is a flexible metallic armor tube 12 and throughA this tube and through the casing 5 I lead Vthe necessary conductors 13 and 14 by which current is conducted to the igniter element.v p

The conductor 14 is connected to a metal rod 15, nickel chromium alloy for example, which is mounted in the insulating member 7 while the conductor 13 yisconnected to a post 16 also mounted in the member 7. The

insulating member 7 also carries a metal sup,

I flat met-al bridge plat-e 18 which may also be of nickel chromium alloy, lthis plate being rigid with the rods.

' The stud or post 16 to which the conductor 13 is attached also secures a spring arm 19 in place to the insulator 7. This spring arm is cup shaped asshown at 20 at the end remote from its point of atachment to the stud 16 and has secured to it a cup shaped memb er 21 preferably of aluminum.

' Intermediate the aluminum member 21 and the end of the spring contact 20 and the bar 18 at the outer ends of therods 15 and17 is igniter element 22, an aluminum plate 23 or other metal being provided between the outer end of this element and bridge plate 18. The tension in spring contact arm 19 holds the igniter element infirm engagement with the cup shaped member 23 so that good contact-is obtained at each end of the igniter element.

- The igniter element 22 as above pointed out is of such a character as to be exceedingly well adapted for my purpose in that the same presents a large or extended incandescent area and is operable on the usual power circuit, 110 volts for example, direct, 1. e., without the interposition of a step up transformer, and by reason of its extended surface or area is capable of use'with fuel oils having a much higher fiash point than the fuel oils which are usable with sparkin the construction of the igniter element isr known commercially as Globar and is the tradename of a productmanufactured by the Globar Corporation vof Niagara Falls, New

York. This product is a nonmetallic resistance element and resembles in appearance the compound known commercially asv silicon carbide. It has a working temperature up to 2750o F., its coseliicient of expansion is.

extremely low, being one-halfr that of iron, l

while rapid heating or quick cooling has no elfect on the structure of the element. Another advantage of this type of elementis that the same quickly attains working temperature and will successfully withstand reasonable overloads.

I have mentioned above that at each end of the heating element 22 I provide an aluminum plate, these plates beingl designated 20 and 23. These plates are provided for preventing the formation at each end of the igniter element of a lm of non-conducting material, the operation of the element 22 without these plates apparently having some chemical reaction with the bar 18 for instance causing the formation of a film which is a poor conductor of electricity. Aluminum overcomes this drawback efectually, although it is to be understood that other metal may be substituted therefor if desired.

In addition to the foregoing I find it of advantageto provide for the automatic closing of a circuit through the igniter when the igniter has been moved to or approximately to its operative position with respect to the burner tube 2. VIn this connection I pivot a plate 24 to any convenient part of the apparatus as to a bracket 25 for instance. This plate has a sloping face 26 as shown on Fig. 2 and carries on its upper side a mercury contact tube 27 suitably connected to the conductors 13 and 14 as shown.

The location of the plate 24 and the shape of its face 26 is such that whenthe a paratus is moved to the left as viewed in Flg. 2 the ange 6 will engage theplate and gradually `move the same about its pivot to tip the tube 27 and close a circuit through the heat ing element 22 at the time the igniter apparatus has been advanced to approximately its operative position with respect to the burner tube. Obviously upon movement of the igniter in the opposite direction toward inoperative, position the tube 27 will restore f I have provided ignition apparatus particularly adapted for oil burmng apparatus, wherein the igniter element is adapted to be moved into and out of operative position with respect to the fuel or other material to be ignited, the igniter element being of such a type as to present a large extended incandescent area to the material to be ignited1 this large area enabling the apparatus to be used with oils having 'a much higher flash points than oils with which ignition apparai tus of the spark gap type are usable.

It will be seen also that my apparatus eliminates the necessity for transformers and the like in its operation, with their attendant dificulties and disadvantages.

It is evident that various modifications may be made in the'eonstruction above described within the purview of-this invention.

What I claim is 1. Ignition mechanism comprising an electrode, means for moving the electrode into and out of operative position, a switch for controllin a circuit to said electrode, a pivoted` mem er mounting said switch, and means carrying said electrode and movable therewith and adapted to engage said -pivoted member to close said switch when the electrode is moved toward closed position.

2. Ignition apparatus comprising a fixed housing, a casing therein, means for moving said casing in said housing, an electrode o non-metallic material carried by said casing and movable therewith into and out of operative position, and a switch closedV by the movement of said casing to carry the electrode into operative osition, for closing a circuit to said electro e.

3. Ignition apparatus comprising a nonmetallic resistance element as an electrode, a pair of metal supporting rods, a metal bridge across said rods, metal means intermediate the electrode and said bridge member for preventing the formation of a nonconducting film between the electrode and bridge, a spring contact for pressing the `electrode into contact with said intermediate metal means, and metal intermediate the spring contact and electrode for preventing the formation of a non-conducting` film between the contact and electrode.

This specification signed this 5 day of April, 1929.

JAMES N. MACRAE 

